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Weather Summary

Strong inversion in the morning. We climbed above the cold pool of air around 7,000'. Light winds blowing at upper elevations out of the W.

Avalanche Observations

We did a fair bit of glassing and did not observe much avalanche activity, outside of the reported slide above. We did see a faint crown (?) off the S ridge on Copper at 8,500' on a SE facing slope that may be a part of the 1/3 pattern of activity but confidence on that is low.

Snowpack Observations

We were out to collect additional data on the 1/3 weak layer, which generally appears to be a crust+facet combo, based on the distribution of recent avalanche activity. We dug in a few locations on slopes that face the sun (SE-S-SW) looking for it and did not find an obvious crust near this interface (within the upper 3' of the snowpack). We did find some subtle layers of facets within the snowpack that produced ECTNs with moderate force (down 30-60cm), as well as a widespread temperature/wet snow crust, buried down 20cm. This upper crust corresponds to a period of warming, wet air, and precipitation on 1/6. At lower elevations this almost feels like a rain/drizzle crust, but its hard to say with certainty. This produced some ECTNs with easy force and would make for an ugly weak layer if we had a big load on the way. However, given the forecast and ambient conditions it may just end up faceting away. Stay tuned.

We dug down to our old friend 12/11 on a NE aspect at 8,300' to take a look. HS was between 240 and 280 at this aspect and elevation, which may be a slight overestimate based on light wind loading that likely occurs regularly on this slope. 12/11 was located 200-210cm down, under a slab that smoothly graded from F- to 1F in the upper 50cm, then from 1F quickly into P and then K. Meaty. In this location the layer presented a few sets of P hard crusts (originally ambient temp crusts) interspersed with thin bands (1-2cm thick) of 1F to 1F-, 2-4mm DHxr. Grains had lost striations and edges on cups (cups were barely recognizable in most places). This layer looked significantly better than what I observed in the Sawtooths the day before (12/9).

There is a lot of faceting going on in the upper snowpack, thanks to the daily temperature swings and ample amounts of solar radiation. Even in deep snowpacks (like around Banner) the faceting is penetrating the upper 30+cm of the snowpack. Some SH growth was apparent down low but this did not extend above 7,000' where we traveled. MFcr (radiation recrystallization) is forming on solars down into the upper 20 degree range (slope angle).

Avalanche Problems

Problem	Location	Distribution	Sensitivity	Size	Comments
Persistent Slab	N E S W	Isolated Specific Widespread	Unknown	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Weak Layer(s): Jan 3, 2022 (MFcr) Comments: Rose shaded based on where it is suspected to be most likely. Need a steep slope for this thing it seems like. We looked for this layer but did not find anything obvious beyond some weakly developed FCsf where this interface would be.
Deep Persistent Slab	N E S W				Weak Layer(s): Dec 11, 2021 (FC) Comments: Almost hard to call this a problem, but noting it due to its presence and the fact that we dug down to it.

We did not directly encounter any avalanche problems today. Wind slabs did not exist in the terrain we traveled in, the deep persistent slab is almost hard to describe as a problem (in the terrain we traveled in), and the 1/3 persistent problem kept us out of terrain that it likely exists in. Cornices are massive and present a real hazard, we saw evidence of plenty of large cornice failures during the storm as well as some impressively unstable-looking cornices and some large gaps between ridgelines and cornices as these beasts creep their way off the ridge.

Terrain Use

We avoided large, open, steep, rocky, wind-affected terrain.